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Vulnerability · Published Jul 10, 2026 · Assigned by GitHub_M

CVE-2026-55370Logto: TOTP code can be replayed within the RFC 6238 validity window (one-time use violation)

Medium 6.4

In plain English

A medium-severity security flaw in logto from logto-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities).

Severity (CVSS 3.1)6.4Medium
Exploit odds (30 days)0.3%top 72.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 1.41.0, Logto's existing TOTP verification accepted a successfully used TOTP code again while the code remained inside the RFC 6238 acceptance window because the verifier used otplib's stateless check with window = 1 and did not persist or compare the accepted TOTP time-step counter. An attacker who has the victim's first factor and captures a live TOTP value can replay that value to satisfy MFA during the same acceptance window. This issue is fixed in version 1.41.0.

Affected products (as reported)

VendorProductVersions
logto-io logto < 1.41.0

Weakness: CWE-294 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

References